Afternoon all

I'm slowly getting round to wiring up the car and trying to remember everything so I don't end up back tracking to put things right.

Battery isolator switch, I understand it's wise to have one fo SVA as it counts as one of your immobilsers. If I understand it should be situated where it can't be switched whilst driving.

Here are My questions.

1) Is under the bonnet near the battery for ease of wiring a good place? if not where would people recommend?

2) How are these things wired? does it just go in the positive lead to the starter? again if I'm wrong how is it wired?

3) All the ones I've seen have the re removeable key, once in the "able to start engine position" can the key be removed to prevent accidental loss? is this type of switch what most of you are using and what make/place to buy?

Thanks for the continued assistance everyone it's much appreciated.

Nigel

Can't help on the location etc as I haven't got that far yet.
I was going to say that if your car has an alternator then you will need the more expensive FIA type otherwise the engine could well run on making its use as a cut-off somewhat pointless. This may not be an issue if just using it as an immobiliser but as the FIA one (more expensive) is only about £20 it's hardly worth taking a chance.

quote:

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Originally posted by jabbahutt

1) I have mine in passenger foot well. If what you say about having it accessible from driver's seat, then surely that wold not be possible if it was under the bonnet?

2) Yes, between bsttery and starter.

3) The key is spring loaded and you need to turn it - it will not drop out when in "on" position. Why would you want to remove it? If you do remove it, the engine keeps on running as it does not kill the power to the ignition. You would need to take the igntion wire AFTER the switch.

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You could disguise the switch as something else like a fag lighter etc to make it easier to use

The problem is this:

If you use the cheap one. It completely disconnects the Battery.
Thus the Alternator has no reference point (the battery). This causes the regulator in the Alternator to go berserk (my description) and thus it usually goes phut!
ie it will not be able to hold the voltage steady as there is no reference point (12V battery).

The best solution is to use the FIA ones. These have additional contacts and I would wire the ignition or the ignition coil through these (I dont know if they are normally open or normall closed contacts)
You would need to check this, and wire apropriately.

When the switch is operated it kills the engine, and thus preventing any Alternator damage, or damage to any other electronics by the Alternator generating high voltages due to the regulator loosing its reference voltage.

The cost of the more expensive switch, is minimal, compared to the cost of a new electronic speedo or rev counter. or a digidash etc.

So dont skimp, and do the job properly first time. It dont cost a fortune.

Hello Nigel

I would certainly recommend an FIA switch will will kill the engine rather than just a battery isolator that will allow the engine to run from the alternator.

I fitted my switch to the scuttle within reach as per the Blue Book. This was fine for SVA but the Tester said that for anti theft it would be better to be mounted under the bonnet.

I' try to attach a picture of the wiring diagram

As said, the key is spring load and has to be depressed to turn to the off position before it can be removed. It definitely cannot fall out when in the ON position.

I hope that covers everything.

atb

John

Hi if it is off any help here is the diagram for the FIA version.

Edited due to being beat by 30second by the above post.

Cheers Matt

[Edited on 25/1/08 by procomp]

Many thanks for the assistance fellas, it's amazing how posting a questions throws up information i'd never even considered like engine run on etc.

I can know go an source an FIA switch. I take it that all FIA approved switches will isolate the battery and also kill the engine as mentioned in previous posts as I'd hate to get the wrong kind of switch.

Lastly if I mounted the main isolator switch under the bonnet to act as one of the security devices is there a way to wire in a cut switch in the interior for use in an accident to kill the engine?

Thanks again
Nigel

Just been through that one.
The reason to use an FiA one is that it incorporates a ballast resistor in the charging circuit. As I understand it this means you don't burn out the alternator if the engine is still running when, or if, you use the kill switch to stop the engine.
Mine is on the outside just under the bonnet side, the idea being that the engine can be stopped externally in the event of an accident. It's also as near the battery as possible to reduce the runs.
Normally there's a wiring diagram supplied with the switch.
Don't forget however that for SVA (or is it MOT?) side lights must operate as parking lights regardless of whether the kill switch is off or on so include that in your wiring plans.
Cheers, Pewe

I thought that you did'nt need a cut off switch for SVA, the steering lock on the sierra column is enough to count as an anti-theft device?

Dan

quote:

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Originally posted by Bluemoon
I thought that you did'nt need a cut off switch for SVA, the steering lock on the sierra column is enough to count as an anti-theft device?

Dan

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quote:

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Originally posted by jabbahutt
Many thanks for the assistance fellas, it's amazing how posting a questions throws up information i'd never even considered like engine run on etc.

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Steering column lock and ignition switch will suffice, no need for cut off switches or immobilisers - as per standard car. I fitted FIA switch anyway and was told I didn't need it.

quote Lastly if I mounted the main isolator switch under the bonnet to act as one of the security devices is there a way to wire in a cut switch in the interior for use in an accident to kill the engine?

Surely your ignition switch will do this

Why would you need the FIA master switch if it's only being used as an immobilizer? ie being used after the engine is turned off at the iginition.
it's sva not scrutineering

Why would you need the FIA master switch if it's only being used as an immobilizer? ie being used after the engine is turned off at the iginition.

Absolutely right but if you ever have any plans to race then by fitting an FIA switch you've killed two birds with one stone.

I got through SVA without having sidelights on a separate circuit and the Special which had the same arrangement got through MOTs without any problem. However, I can see the sense in being able to immobilise the car but also be able to leave the parking lights on.

John